1. Field of the Invention
The present invention relates to a telescoping and rolling (TandR) cover assembly for barges and the like.
2. Related Art
Barges are commonly used to transport a large variety of materials, such as grain, that must be protected from the natural elements. Over the years, a wide variety of covers have been designed to meet this need. Although some cover systems utilizing continuous covering material are known (see, for example, earlier U.S. Pat. No. 4,461,232), sets of adjacent cover sections are more commonly used. Such covers fall into one of two categories: lift-off and rolling. Lift-off covers, as their name implies, are lifted off and placed on barges usually using cranes located at a dock. The use of a crane for lift-off covers adds to the overall operating expense of these covers. Furthermore, because a crane is required, the covers cannot be opened prior to the barge arriving at a dock, resulting in still further expense for dock time. Finally, lift-off covers are subject to damage as a result of lifting the covers off barges, stacking the covers on the dock, and placing the covers back on barges.
Rolling covers are equipped with wheels or glides so that they travel along tracks. The rolling covers are generally designed such that at least some of the covers can be rolled or telescoped under others to expose at least a portion of a barge cargo hold. Covers such as these are known in the art as TandR covers.
An example of a steel TandR cover assembly is shown in U.S. Pat. No. 4,237,809, granted to Hickmann. There are several drawbacks associated with using steel barge covers, including corrosion and weight. For example, steel covers require a crane or outside power to open and close. FRP (fiber reinforced plastic) is a natural alternative; however, there are problems associated with using FRP for TandR covers. First, the lighter weight of FRP actually makes the covers more prone to being pulled off the track on which the wheels or glides travel. This problem is father exacerbated by use of the covers as tie points by barge and/or tug boat personnel. Damage to covers often results when covers are pulled off the track, besides making them inoperable. If a crane is required to place the covers back on track, the potential for further damage is increased.
A second issue with the use of FRP TandR covers concerns securing the covers when stacked on a dock (although the covers are telescoping, there will be situations in which they must be stacked on the coaming ends or removed entirely as discussed further below). Because of their light weight, TandR covers are more subject to being blown off a stack in strong winds, although steel covers may also be blown off by wind. Prior art FRP covers must therefore be tied down using extra equipment (rope, latches, etc.) when stacked; there are no provisions on the covers themselves for securing the covers. In strong winds, FRP covers may also be blown off the tracks or rails they ride on.
Referring now to TandR covers generally and specifically to U.S. Pat. No. 4,237,809, another problem associated with known TandR covers is the relative complexity of track mechanisms associated with these covers. For example, the ""809 patent requires four separate tracks on the barge coaming for an embodiment in which four covers are xe2x80x9ctelescopedxe2x80x9d into one.
What is needed is a simple, reliable, and lightweight telescoping and rolling barge cover.
The present invention meets the aforementioned need to a great extent by providing a telescoping and rolling cover set manufactured using a lightweight material such as FRP. In preferred embodiments, the cover sections include anti-derailment clamps which provide a tie point, preferably in the form of a ring, while preventing the covers from being pulled off the track when the anti-derailment clamps are tied onto. The anti-derailment clamps can pivot when a substantially vertical force is applied to the tie point. Consequently, the clamps disengage the track and/or coaming when a crane ties onto the ring and lifts, thereby allowing the covers to be lifted off.
In preferred embodiments, the anti-derailment clamps include extensions which engage anti-derailment clamps attached to a cover section below when cover sections are stacked. In this way, they are prevented from being blown off the stack when exposed to high wind conditions.
In one embodiment of the invention, four covers may be telescoped into one along a single track on each side of a barge coaming. In a second embodiment of the present inventions, four covers may be telescoped into one along two tracks on each side of a barge coaming. In preferred embodiments of this type, both ends of at least one of the covers ride along a track on the barge coaming while at least one of the covers rides along a track on the barge coaming on one end while riding along a track attached to an underlying cover (as used herein, underlying cover refers to a cover onto which another cover may be at least partially telescoped) at an opposite end.
In yet another embodiment, two covers may be telescoped into one. In preferred embodiments of this type, two tracks are preferably provided such that both ends of each cover in a telescoping pair may travel along one of the two tracks at all times.
In preferred embodiments, the track is in the shape of an I beam and the cover sets include wheel assemblies with weight-bearing wheels that roll along the top of the track. A transverse guide wheel that rides along the top inside vertical surface of the I beam track to guide the cover along the track is also included in some preferred embodiments. In alternate preferred embodiments, the wheel and tracks are angled inwardly and may include a flange to keep the wheels on the track. In some embodiments, the track is simply the flanges of an H beam oriented such that the flanges are vertical.
Another aspect of the present invention is the provision of a stacking shelf. The stacking shelf is provided for those situations in which the covers must be removed from the rails and stacked onshore. The stacking shelf provides a weight bearing platform for stacked cover sections.
A method for fabricating FRP covers is also disclosed. In preferred embodiments, the center portions of cover sections are identical, while the height and width of the side portions (the part of the cover section nearest the coaming and tracks) of the covers are varied so that the resultant covers may telescope. Plugs including the common center sections and variable side sections are created for each cover section. Then, two mold halves are created from the plug such that the molds can produce the cover section with only a single seam. The method utilizes fewer molds than known methods, thereby reducing the number of seams to produce a better looking cover and reducing the amount of material required to fabricate the covers. The two mold halves are preferably sized such that they may be shipped by truck as a xe2x80x9cwide load.xe2x80x9d Current regulations dictate that the maximum width for a wide load be 10 ft.